Coffee maker



Oct. 9, 1945. p STRQTHER 2,386,278

COFFEE MAKER Filed Aug. 1, 1942' /e a by i m FmdPJtrol/zer latented Oct.9, 1945 COFFEE MAKER Fred P. Strother, Minneapolis, Mimi assignor toSears, Roebuck and Co, Chicago, Ill, a corporation of New YorkApplication August l, 1942, Saris-l No. 453,193

Nil. 21*3-43 8 Claims.

Th s invention relates to cooking devices, and more pcrticulurly toelectric coffee makers.

An important object oi the invention is toprovide a, coffee maker havinga novel construction arrangement of ports.

Another object is to provide s, novel device for automatically brewingcodes or similar beverages and their ior automatically maintaining thebev eroge st the desired temperature for service.

A iurther object is to provide e. novel releasable :dlter loclzingassembly.

it is also our object to provide novel filter remoi/hog rhesus:

Further objects and advantages of my inven tion will es the descriptionproceeds.

The invention will be understood better upon reference to the followingdescription and the uc= compsuying drawing, in which:

Fig. l iseiverticul' sectional view of on illus trutive coffee makerbuilt in accordance with the invention, taken as indicated by the linel-!l in Fig. 2 is g, plan view telzeo as indicated by the line lb -2 inFig. l;

3 is an enlarged fragmentary sectional view taken e indicated by theline 3-3 in Fig. 2;

fig. d is e sectional plan view telsen as indicated by the line 3- 3 in3;

Fig. 5 is an enlarged fragmentary plop sectiousl view token-es indicatedby the line 5-5 in Fig. 6;

Fig. 6 is s. fragmentary vertical sectional view taken as indicated bythe line 5-6 in Fig. 5.

Referring now more particularly to the drawlug, there is shown forillustrative purposes a lower pot ill having a suitable preferably heat=insulating heridle ti and pouring spout Ho, and a, base 52 with four orany other suitable number of heat-insulating feet it and a, large mouth65 embracing a. rubber or other suitable gasket ring it by means ofwhich an upper pot i8 is supported. The lower pot it has a heatconducting plate floor it soldered or brazed as at or other wisesuitably connected to the side wall 22 of said lower pot, and, spacedtherebelow a, disc or pressure plate 23 spot-welded as at 24 orotherwise suitably connected to said side wall. The resulting space itis occupied by an electric'reslstence heating unit 2'5 such as a, wire28 wound about and between upper and lower mica sheets 30 suitably heldin assembly with the pot lo, said sheets being portions of a, wrapper orenvelope if desired and insulated electrically from said pot etc.

Secured to and under the disc 23 as by screws 32 (Figs. 5 and 6) is asupporting plate 33 to which a toggle lever 34 is pivoted as at 36, saidlever being urged selectively toward one or the other of two stops 3'!aiid 38 by a spring Ml anchored at M to the lever at one side of thepivot and at 422. to the plete 83 at the opposite side of the pivot.

The lever 3 5 has depending esrs dd end 45 to which nuts to may befastened or welded as at All to receive screws 38 grid respectively,

sdepted to be edlusted toward. and away from each other. Disposed inlost motion relation to and between the screws id and is the free endill of o thermos-tot bimetcl whose other end is anchored as at 55 by sscrew or rivet between the :iorh arms 56 of e. hoot transferring studdepending from the hot plate to through an opening $9 in the disc 23."Erie our has an eiztension 6t carrying a porcelain or other iusu-=lotion pin 52 engageeble with the movable spring arm Gil of a switch toclose the some, the switch being however normally open. The arm St hasat contact Gd eugegeoble with a contest on 2. second spring arm 69 or"the switch, the other ends of sold arms being anchored as at betweenseparated by suitsble insulating blocks ll held between e plate '53 ande, bracket ld cerried by the plate it out l6 welded or fostened as his"ll or otherwise secured adjacent the free end 50 of the bimetsl 52receives a. screw it having a porcelain or other insulating end ddengugesble with the switch arm 63 to close the switch. One of the switcharms and 69 is wired as at ill to one terminal 822 of the heatingelement 2%"; and the other switch arm and the other terminal d4. of theheating element 28 are wired as at to prongs suitably secured to andinsulated from the base housing l2 and shielded by e shell or socket Bl(Fig. i).

The upper pct 03 has a, floor open centrally as at 9i and has brazed asat $2 or otherwise suitably secured thereet o tube adapted to terminateshort of the floor 953 of the lower pot. A rod 96 is provided, having a,stem 9'8 adapted to be received in the tube 534 and having a handle titarranged to be grasped and manipulated conveniently through the mouthIltll oi the upper pot. A formic idl about the stem Bl and having adished spring spider or other suitable perforated member W2 welded orotherwise fastened thereto is held against longitudinal displacement byobutments M5 which may be upset from the stem. A. pressure plate Hi6also in the form of a spider Or other suitable perforated member may beintegrel with or suitably fastened to e sleeve 108 adapted to betelescopically assembled with the ferrule toll and to be releasebly heldin e. predetermined relation with the spring member 32 under tension ofthe latter by meens of a snap spring or pawl ills releesably received ina circumferential groove Hill in. the ferrule. The plate M36 is adaptedto seat in the central depression M2 in the fioor 90 of the upper pot,with the upper surface of said. plate substantially flush with theadjacent upmr surface Ilia of the floor 90.

A cloth or other suitable filter lit! is adapted to be resilientlyclamped between the spiders i032 and I06 and to rest on the floor all,the filter having a central hole H4 substantially in register with thebore of the spider m6 and its sleeve ltd.

Secured as at M8 to the lower end ill of the stem 97 is a sleeve Milcarrying a spring pawl I28 cooperative with teeth 82E on a ratchet studI22 centrally secured as at 26 to and projecting up from the floor it ofthe lower pot iii. The lower end of the tube lid is preferably flared orbelled as at 925 and the top 925) of the stud is preferably rounded toguide the tube over and about the stud as the tube descends, the top ofthe stud also readily camming the pawl lfid aside as the latterdescends. The stud is flattened at one or opposite sides 21253 to afiordin effect a plurality of bayonet joint adjustments with the pawl i2@.Thus, as the pawl 826i descends it may snap over the teeth iii or it maybe disposed as shown in dotted lines in 4, 90 from the position shown infull lines, until the lower spider ltd is seated in the depression H2,and then, if in the dotted line position, it is turned 90 to engage theappropriate ratchet tooth whereby to releasably lock the filter assemblyin operative position and also releasably lock the two pots together.The upper spider M32 is sufiiciently resilient to enable the user topress it down until the pawl engages a tooth low enough to insureagainst any looseness or rattling of parts. Rotation of the handle 98 90from the full line position will release the pawl and allow the assemblyto be removed. The inside diameter of the lower spider iiili, sleevei838 and filter are such as to enable them to slip past the spring i2@and tube lid, whereby an old filter may be readily replaced by a newone. The entire filter ensemble is removable and insertable through themouth idil of the upper pct 08.

As seen in Fig. 5, the thermostat 52 moves in the direction as it coolsand in the direction H as it heats. Accordingly, when the device is coldthe thermostat button dd is in engagement with the switch arm t3 andholds said arm against its spring resistance (and possibly also thespring resistance of the arm 59) in the position shown, wherein thecontacts 66 and fill are engaged and hence the switch 65 is closed. Atsuch time, also, the toggle lever Si is on the near side of dead center,i. e., the side on which the stop pin .38 is disposed, where the leveris held by the toggle spring (it, which accordingly holds the button 62against the switch arm 63 in switch-closing position.

In making cofiee with this apparatus, the plug socket i3l, connected toa wall socket (not shown), is plugged in at 8? to the prongs 8t,projecting from the base it, to supply electric energy to the heatingelement 23. As the temperature of the hot plate l9 rises, the water inthe lower DOt it steams. At the same time, the bimetal 52, becomingwarm, moves in the direction H, and may become free of the switch arm 63but does not move sufiiciently to withdraw the button 62 sufliciently toallow the arm 63 to spring open. The steam ultimately drives the liquidup the tube 9d, and thereafter, due to the reduction of water to beheated by the hot plate IS, the temperature of the plate rises rapidly,as does also the bimetal 52, which engages the pin 48 and promptly tripsthe lever 36 past dead center into engagement with the stop 37, the

springing to openproximately 180 F., for example, the adjustable Eliporcelain-tipped point it has engaged the switch arm 63 and moved it toswitch-closing position, without however having moved the lever 3d atall or at any rate sufficiently to trip the lever past dead center. Thetemperature of the coffee accordingly again rises, but when it hasreached approximately 185 F., for example, the bimetal has againretrogressed to a point enabling the switch arm 63 to spring open. Theconsequent cooling restarts a series of these cycles whereby thetemperature of the coffee may be maintained indefinitely at a propertemperature between say F. and F. for serving.

When the socket plug l3i is withdrawn from the coffee maker, therebydisconnecting the letter from the line, the bimetal 52 cools and movesinto engagement with the point 58 on the lever 35 which, at atemperature of approximately 125 F., for example, trips past deaclcenterand forces the switch arm 63 into switch-closing position, as shown inFig. 5, ready for repeating the aboveexp'lained operation uponreconnection with the line for making another pot of coffee andretaining it at the desired temperature for serving.

It is evident from the foregoing that with my construction the humanelement is eliminated since there is nothing to preset in order to placethe appliance in operation.

The parts may be readily calibrated or constructed to open and close theswitch at any desired temperatures. All calibrations may be made atthefactory and thereupon all screws may be soldered or brazed in place.

The feet id may be mounted on a base plate I35 which may be attached asby screws lit to lugs or other means I38 spot-welded as at l39 orotherwise suitably attached to the heating element housing.

The filter unit is assembled by slipping a filter cloth and thereafterthe lower spider I06 with its sleeve IE8 past the pawl E29 until thespring I09 snaps into the groove H0, thereby resiliently clamping thefilter cloth against the spring spider H32. To remove the cloth thisprocedure is reversed, the spring H39 readily snapping out of the grooveI I0 upon being pulled down by the user.

Various modifications coming within the spirit of my invention maysuggest themselves to those skilled in the art, and hence I do not Wishto be limited to the specific form shown or uses mentioned, except tothe extent indicated in the appended claims, which are to be interpretedas broadly as the state of the art will permit.

I claim:

1. A temperature control for a heating element comprising a switchcontrolling the supply of electrical energy to said element, said switchincluding a movable contact biased toward open circuit position, athermostat responsive to the temperature of said heating element, meansoperative by said thermostat at a predetermined minimum temperature tomove said contact into closed circuit position, and means operative bysaid thermostat at a predetermined maximum temperaturte to allow saidcontact to spring to open circuit position, said thermostat beingthereafter operative at an intermediate temperature to move said contactto closed circuit position and at a higher temperature to allow saidswitch to open.

2. A temperature control for a heating element comprising a switchcontrolling the supply of electrical energy to said element, said switchincluding a movable contact biased toward open circuit position, athermostat responsive to the temperature of said heating element, meansoperative by said thermostat at a predetermined minimum temperature tomove said contact into closed circuit position, said means releasing itscontrol of said contact as the thermostat responds to increasedtemperature of the heating.

element, supplemental means operative to hold said contact in circuitclosing position during such increase of temperature, and a lost-motionconnection by which the thermostat releases said contact from saidsupplemental holding means at a predetermined maximum temperature,allowing said contact to spring to open circuit position, saidthermostat being thereafter operative at an intermediate temperature tomove said contact to closed circuit position and at a higher temperatureto allow said switch to open.

3. A temperature control for a heating element comprising a switchcontrolling the supply of electrical energy to said element, said switchincluding a movable contact biased toward open circuitposition. athermostat responsive to the temperature of said heating element, meansoperative by said thermostat at a predetermined minimum temperature tomove said contact into closed circuit position, said means releasing itscontrol of said contact as the thermostat responds to increasedtemperature of the heating element, supplemental means operative to holdsaid contact in circuit closing position during such increase oftemperature, and a lost-motion connection by which the thermostatreleases said contact from said supplemental holding means at apredetermined maximum temperature, allowing said contact to'spring toopen circuit position, said thermostat being thereafter operative at anintermediate temperature to move said contact to closed circuit positionand at a higher temperature to allow said switch to open, saidthermostat responding to said pre- 7 determined minimum temperature byreturning the said contact to closed circuit position and by actingthrough said lost-motion connection to return said supplemental means toits contact-holding position.

4. In an automatic coffee maker, an electrical heating element and atemperature control device therefor comprising a switch controlling thesupply of electrical energy to said element. said switch including amovable contact yieldingly biased toward open circuit; position, athermostat responsive to the temperature or the heating element andcarrying means which engages said contact and holds it in circuitclosing position at a predetermined minimum temperature, a supplementalholding member also maintaining said contact in circuit closing'positionunder minimum temperature conditions, and spaced abutments on saidsupplemental member engageable alternatively by the thermostat andforming a lost motion connection therewith, said thermostat withdrawingfrom its engagement with said contact upon increase of temperature andthereafter engaging one of said abutments to withdraw said supplementalmember from its holding position in response t a predetermined maximumtemperature, allowing the contact to spring to open circuit position,said thermostat then re-engaging said contact and moving it to circuitclosing position at an intermediate temperature and recurrently openingand closing the circuit in response to temperature changes rangingbetween such in termediate and a higher temperature.

5. In an automatic coffee maker, an electrical heating element and atemperature control de vice therefor comprising a switch controlling thesupply of electrical energy to said element,

Ill

said switch including a movable contact yieldingly biased toward opencircuit position, a thermostat responsive to the temperature of theheating element and carrying means which engages said contact and holdsit in circuit closing position at a predetermined minimum temperature, asupplemental holding member also maintaining said contact in circuitclosing position under minimum temperature conditions, and spacedabutments on said supplemental member engageable alternatively by thethermostat and forming a lost-motion connection therewith, saidthermostat withdrawing from its engagement with said contact uponincrease of temperature and thereafter engaging one of said abutments towithdraw said supplemental memher from its holding position in responseto a predetermined maximum temperature, allowing the contact to springto open circuit position. said thermostat then re-engaging said contactand moving it to circuit closing position at an intermediate temperatureand eventually engaging the other abutment of the supplemental memberand returning said member to its holding position in response to apredetermined minimum temperature of the heating element.

6. A coffee maker comprising a hot plate, an electric circuit includinga resistance wire and a switch, sai'd switch including acontact-carrying spring arm normally in open-switch position, meansincluding a toggle lever spring biased to move said arm selectively intoclosed-switch and open-switch positions. and a thermostat influenced bysaid hot plate and having a portion movable in a path parallel to thetoggle movements of said lever, said lever and thermostat having a lostmotion connection enabling said thermostat to impart switch-opening andswitchclosing movements to said lever at predetermined upper and lowertemperatures of said plate, said thermostat being movable attemperatures intermediate said upper and lower temperatures withoutactuatingsaid lever, and being operative, when said lever is inopen-switch position, to close and open said switch at certain of saidintermediate temperatures.

7. Thestructure set forth in claim 6, and means for preventing excessivevthrow of said lever in each direction.

8. The structure set forth in claim 6, and means for rendering saidswitch operative selectively at various upper, lower and intermediatetemperatures.

mm: P. smo'rrma.

